Electron discharge device seal



Feb. 1; 1949.

P. R. HANSON ET AL 5 ELECTRON DISCHARGE DEVICESEAIQ Filed May 21, 1945 Wa n 7mm.

Patented Feb. 1, 1949 ELECTRON DISCHARGE DEVICE SEAL Per Roland Hanson, Winchester, and Harold W. Ulmer, Belmont, Mass, assignors to Raytheon Manufacturing Company, Newton, Mass, a

corporation of Delaware Application May 21, 1945, Serial No. 594,850

Our present invention relates to electrondischarge devices, and more particularly to seal structures for the electrodes of such devices.

One of the objects of our present invention is to provide a glass-to-metal seal for the electrodes of electron-discharge devices, having greater mechanical strength than those heretofore employed.

Another object of our present invention is to so construct such a seal that it remains vacuumtight under wide variations in temperature.

In the accompanying specification we shall describe, and in the annexed drawing show, an illustrative embodiment of the electron-discharge devices of our present invention. It is, however, to be clearly understood that we do not wish to be limited to the details herein shown and described for purposes of illustration only, inasmuch as changes therein may be made without the exercise of invention and within the true spirit and scope of the claims hereto appended.

In said drawing, the single figure is a partial side elevational, partial longitudinal sectional View of an electron-discharge device incorporating an electrode seal made in accordance with the principles of our present invention.

Referring now more in detail to the aforesaid illustrative embodiment of our present invention, and with particular reference to the drawing illustrating the same, the numeral 5 generally designates an electron-discharge device which may include, for example, a cathode structure 6, a control-grid structure I, an anode structure 8, and a pair of glass envelopes 9 and I0.

While the cathode structure 6 has not been shown in detail, it may include a cylindrical head H, made of nickel or the like, provided with a highly electron-emissive coating l2, for example, of the alkaline-earth metal oxide type. Said head may enclose a heating filament (not shown) to which current may be conveyed through a coaxial line 43.

While the seal construction of our present invention is not limited in its application to any particular electrode, it is here shown as applied to the control-grid structure 1.

Such a control-grid structure may include a rod l4, made of material of high heat-conducting properties, for example, copper, and having appreciable cross-sectional area. The outer end l5 of said rod may be enlarged, and provided with a plurality of heat-dissipating fins l5 bridged by a plurality of spaced, flat electrical conductors ll presenting short R.-F. energy paths.

.6 Claims. (Cl. 250-27.5)

Surrounding the rod 14, with its upper edge abutting the undersurface of the lowermost of the heat-dissipating fins !5, is a thin, conducting sleeve l8 having, near its lower end, an inwardlydirected annulus i9 which is centrally apertured to receive said rod 14; and nesting within the lower portion of said sleeve, and secured to the annulus l9 and the lower end of the rod I4, is a thimble 20.

Fixed, as by being welded, to the outer surface of the thimble 20 is a multiplicity of grid wires 25 which surround the cathode head I l and have their lower ends secured to the outer surface of a flanged ring (not shown) or any other suitable means of support.

The anode structure 8 may comprise a pair of centrally-apertured, annular members 22 and 23 made of highly conductive material, such as copper, said annular members being provided at their central apertures with diverging, feathered edges 24 and 25, and recesses 26. The latter are adapted to receive a ring 21 so as properly to align the H annular members 22 and 23 during assembling, thereby assuring accurate positioning of the cathode and grid structures with respect to each other.

The envelope 9 is sealed at one end thereof to the outer conductor of the coaxial line !3, as at 28, and it is sealed at the other end thereof to the feathered edge 24 of the annular member 22, as at 29.

The envelope I0 is sealed at one end thereof to the sleeve 18 of the grid structure I, as at 30, and it is sealed at the other end thereof to the feathered edge 25 of the annular member 23, as at 3i, the inner surface of the sleeve !8 being backed, in the region of the seal 36, with a ring 32 of glass, whereby the materials of which the sleeve and envelope are made are caused to expand and contract substantially to a like degree, and thus prevent separation.

This completes the description of the aforesaid illustrative embodiment of our present invention. It will be noted from all of the foregoing that we have provided a seal construction for the electrodes of an electron-discharge device which has great mechanical strength, and which, by reason of the manner of applying the same to the electrode, prevents separation of the envelope from the electrode, even under wide temperature Variations.

I Other objects and advantages of our present invention will readily occur to those skilled in the art to which the same relates.

What is claimed is:

1. In an electron-discharge device: a plurality of electrodes; means, connected to one of said electrodes, for conducting therefrom heat developed therein; means, spaced from said firstnamed means, and electrically connected to said last-named electrode, for conducting electrical energy between said last-named electrode and an external circuit; an envelope sealed to the outer surface of said second-named means; and a continuous strip of the same material .as said envelope, secured to the inner surface of said secondnamed means in the region of contact between said envelope and said second-named means.

2. In an electron-dischargezdevice: a plurality of electrodes; a metallic rod of substantial crosssectional area, connected to one-of saide-lectrodes, for conducting therefrom heat developed therein; means, spaced from and surrounding said rod, and electrically connected to said last-named electrode, for conducting "electrical energy *between sa-id last-named electrode and an external circuit; an envelope sealed to theouter surface of :said last-named means; and 1a continu ous strip of thesame material as said envelope, secured to the inner surface of said last-named means in the region of contact between said en velope and said last-named means.

3. In an electron-discharge device: :a plurality of electrodes; means, :connected to one of said electrodes, for conductin therefrom heat developed therein; a metallic sleeve, spaced from and surrounding said first-named means, and electrically connected to said last-named electrode,

for conducting electrical energy between said last-named electrode and ran-external circuit; an envelope sealed to the outer surface of said sleeve; and a continuous strip of the same. material as said envelope, secured to the inner surface of said sleeve in the region of contact between said envelope andisaid sleeve. I

4. In an electron-discharge device: .a plurality of electrodes; ametalliclrod of substantial crosssectional area, connected .to one of said elec- 4 trodes, for conducting therefrom heat developed therein; a metallic sleeve, spaced from and surrounding said rod, and electrically connected to said last-named electrode, for conducting electrical energy between said last-named electrode and an external circuit; an envelope sealed to the outer surface of saidsl'eevep'and a continuousstrip of the same material as said envelope, secured to the inner surface of said sleeve in the region of contact between said envelope and said sleeve.

'5. An'electron-discharge device comprising: an envelope; a plurality of electrodes supported within said envelope; a metallic rod of substantial cross-'sectionalarea, connected to one of said electrodes and passing through said envelope, for conducting fromsaid last-named electrode heat developed therein; and means, electrically connected to said last-named electrode and passing through said envelope, for conducting electrical energy between said last-named-electrodeand an external circuit.

6. An-electron-discharge device comprising: an envelope; -a plurality of electrodes supported r Within said envelope; a metallic rod of substantial cross-sectional area, connected toone of said electrodes, for conducting therefrom heat developed therein; and a metallic sleeve, spaced from andsurroundi-ng said rod, and passing through said envelope, for electrically connecting said last-named electrode w-it-ht an external circuit. VPER ROLAND HANSON.

HARGLD W.

REFERENCES CITED 'The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,941,392 'Heintz Dec. 26, 1983 2,107,945 Hull et a1 lFeb.i8, 1939 2,396,772 Dailey Mar. 19, 1&946 

